The present invention relates to fluid ejection devices, such as those used in fluid ejection cartridges.
When a fluid or ink droplet is ejected from a nozzle or orifice of a printhead, most of the mass of the droplet is contained in the leading head of the droplet. The greatest velocity of the droplet is found in this mass. The remaining tail of the droplet contains a minority of the mass of ink and has a distribution of velocity ranging from nearly the same as the ink droplet head at a location near the ink droplet head to a velocity less than the velocity of the ink found in the ink droplet head and located closest to the orifice aperture. At some time during the transit of the droplet, the ink in the tail is stretched to a point where the tail is broken off from the droplet. A portion of the ink remaining in the tail is pulled back to the printhead orifice plate where it typically forms puddles of ink surrounding the orifice. These ink or fluid puddles, if not controlled, degrade the quality of the printed material by causing misdirection of subsequent ink droplets.
Some parts of the ink droplet tail are absorbed into the ink droplet head prior to the ink droplet being deposited upon the medium. However, other parts of the ink droplet tail neither returns to the printhead nor remains with or is absorbed in the ink droplet, but produces a fine spray of subdroplets spreading in a random direction. Some of this spray reaches the medium upon which printing is occurring thereby producing rough edges to the dots formed by the ink droplet and placing undesired spots on the medium which reduces the clarity of the desired printed material.
It is desirable to minimize fluid droplet tails, as well as the corresponding fluid puddles and spray.
In an embodiment of the present invention, a fluid ejection device has a firing chamber with a feature disposed therewithin.
Many of the attendant features of this invention will be more readily appreciated as the same becomes better understood by reference to the following detailed description and considered in connection with the accompanying drawings in which like reference symbols designate like parts throughout.